In the pharmaceutical industry, much effort has been devoted to the continued development and improvement of controlled release formulations for solid dosage forms, e.g., tablets or capsules. Controlled release dosage forms can facilitate patient compliance with a prescribed dosing regimen by allowing the patient to administer dosages fewer times during a given day which can reduce the incidence of missed or delayed dosages.
Many controlled release tablets include a hole or plurality of holes in their outer membrane to allow digestive fluids to penetrate through the membrane and initiate dissolution of the dosage form. One such example of such a dosage form can be found in U.S. Pat. No. 6,099,859, incorporated herein by reference, in which the dosage form comprises a core, a membrane, and a “passageway” which, by disclosure, may be a hole drilled by a laser. Typically, the digestive fluid enters the inner portion of the tablet which contains the active drug or other medicament, thereby dissolving or suspending the active drug. The active drug or medicament can subsequently diffuse from the inner part tablet at a controlled rate, through the passageway, and allowing said active drug or medicament to be bioavailable to the patient in a desired manner.
The processing of drilled dosage forms often involves use of a tablet processing systems. U.S. Pat. Nos. 5,294,770, 5,399,828, and 5,783,793, incorporated herein by reference, describe various systems for processing drilled tablets. These systems include descriptions, in general, for transporting tablets to a position where they are drilled by a laser. However, none of these systems address the problem of controlling the rate of delivery of bulk tablets from a hopper to the tablet transport system.
U.S. patent application Ser. No. 2002/0175051 describes a vibratory feeding system in which substrates from a hopper are fed onto two separate inclined trays. The trays each contain a central grove and “shedders” which are used to singulate the exit of the components exiting the hopper. However, singulation is not what is needed or desired in the delivery of pharmaceutical tablets to a tablet transportation system.
A common difficulty encountered in pharmaceutical processing is to provide a continuous rate of delivery of bulk tablets from a hopper to tablet transport system. A delivery rate that is too slow may result in the transport system not running at full capacity. A delivery rate that is too fast, can overload the transport system resulting in system failure. Therefore a system is needed which can address this problem by providing a controlled rate of delivery of the dosage form from a hopper to a transport system. The subject invention provides for regulating the delivery of tablets from a hopper to a tablet transport system and can be advantageous to the pharmaceutical industry.